1. Field of the Invention
The present invention relates to handling unwanted email messages by automatically compiling a list of senders of email messages that are to be discarded without scanning.
2. Description of the Related Art
Malicious codes in the form of trojans, worms, adware, spyware, and rootkits have multiplied and grown enormously throughout the last two decades. In the computer and internet technology world there are estimated to be 180,000 viruses in existence, with new ones hitting computers every day. The response to these problems has created an industry of Antivirus and Anti-spyware products. Although malware, such as viruses, trojans and worms are quite prevalent, the most widespread form of malware is unsolicited commercial email, commonly known as spam. The use of spam has grown rapidly and still growing. The corporate world and individual home users are spending millions of dollars to combat spam. Internet Service Providers (ISPs) have to cope with greatly increasing day to day amounts of network traffic due to the increase in spam emails. If spam traffic continues to grow, it may become unmanageable in the near future.
Typically, spam has been fought by the use of software that scans all incoming email messages to determine whether each message is spam. If so, the messages are accordingly marked as ***SPAM*** or quarantined. These actions are taken on each email message that arrives at an email server that is protected by the anti-spam software. Each email message is categorized depending upon the rules that it triggers. These rules can be a mixture of BAYSEAN filtering, honeypot addresses and mail rules, Header and Heuristic analysis, Text Analysis, URL classifications etc. These rules are updated on monthly, weekly or even daily basis depending upon the spam samples collected through researching the entire web. Typically, Anti-Spam products also have options to White-list and Blacklist email addresses. The Emails that arrive from the White-listed email addresses are sent directly to the User's inbox, while the emails that arrive from Blacklist emails addresses are scanned and sent to a quarantine database or discarded.
However, a large ISP can receive millions of emails each day, each of which must be scanned. Other large organizations may receive thousand of emails each day. On an average each mail takes from 15 milliseconds to 400 milliseconds to scan for such spam content. Thus consumes a huge amount of email server time and can in turn create a loss in the productivity of the organization. A need arises for a technique by which the server resources needed to scan incoming emails can be reduced, which will improve server throughput and reduce costs.